Typical microwave and millimeter-wave frequency directive antennas generally comprise cumbersome structures such as waveguides, dish antennas, helical coils, horns, and other large non-conformal structures. Communication applications where at least one communicator is moving as well as radar applications generally require a steerable beam and/or steerable reception. Phased array antennas are particularly useful for beam-steered applications since beam-steering can be accomplished electronically without physical motion of the antenna. Such electronic beam steering can be faster and more accurate and reliable than gimbaled/motor-driven mechanical antenna steering. Phased array antennas also provide a capability to have multiple simultaneous signal beams.
In addition, communications in multiple bands typically require either multiple antenna apertures for each of the bands and/or dual band dish antennas. On-aircraft dishes are generally placed under radomes, adding significantly to the weight of the aircraft, aerodynamic drag, and maintenance complication. A single wide-band phased array aperture minimizes vehicle integration cost and size, weight, and power needs compared to multiple single-band solutions and/or dish antennas. However, conventional low-profile designs using slot rings and/or microstrip patch antennas suffer from mutual coupling that limit their frequency coverage, scan volume, and axial ratio performance.
It is with respect to these and other considerations that the disclosure made herein is presented.